To crimp or not to crimp

[TangoFoxtrot]

As said upthread, the topic of crimping can get HEATED....

For ME=Most all get some kind of crimp-Roll or Tapered, except Bolt Guns.
Also as said upthread, most pressure (Case Neck Tension) is controlled in the size process.

I have found that the easy way to increase neck tension (In two die, rifle dies), is to SLIGHTLY sand down the expander button (or plug if you will). The smaller the expander, the tighter the neck tension.
Segregation of your brass brands, and case wall thickness goes well with this process.

AGAIN Each to His own..Bill.

Yep lol.. this is a conversation that has been going on for a long time and probably will keep on keeping on for a long time..

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[2in1evtime]

I don't crimp bolt gun ammo, i just adjust for neck tension, as to semi=auto it gets crimped be it rifle or pistol, full auto gets a strong crimp!

 

[Goodcat]

Neck tension should be set by proper die setup for bolt guns, not with crimp. However, lightly crimping a rifle cartridge that doesn’t need crimped won’t degrade accuracy to any substantial amount within 400-500 yards. Otherwise it’s not needed and provides an addition point of stacking of tolerances against you with slight variations of neck tension and release from round to round.

In testing, I have found even lightly crimping rifles cartridges (in my experience) to increase a 1-mile load with a standard deviation of 10, to an SD of 20+. When shooting at 1k yards, or at the mile, an increase of 10 SD can significantly impact your shooting.

I personally don’t even crimp smaller magazine fed cartridges like 223 because I have a handle on my neck tension and the recoil is so minuscule, though I recommend it for most, especially heavier recoiling magazine fed rifle cartridges. I do crimp all straight walled pistol cartridges and see no reason why you wouldn’t to avoid potential setback.